The present invention relates to radial motorcycle tires and in particular but not exclusively to high performance or race motor-cycle tires.
Radial motorcycle tires utilize very wide treads which in transverse cross-section are sharply curved to provide good contact with the road surface when the motorcycle is steeply banked when cornering. Maintenance of a consistent ground contact area or `tire footprint` under all conditions is a major problem in determining general vehicle handling. Of particular importance in race motorcycle tires of radial construction is the provision of high cornering power with good stability to maximize cornering speeds under racing conditions.
Present radial motor-cycle race tires have short sidewalls which extend to the tread edges radially and axially outwardly from the tire beads. The beads provide engagement to the wheelrim on tapered bead seats. The sidewalls are reinforced by radial carcass plies which when tensioned by the inflation pressure act together with sidewall geometry to provide location of the curved tread regions to withstand cornering forces.
The sharply curved tread region of the tire is specially reinforced by a reinforcing breaker to give the required structural rigidity to allow for banking over of the motorcycle when cornering while providing sufficient flexibility to allow localized tread flattening in the ground contact patch for achieving good road grip.
Such tires however, due to their uniform breaker structures, do not provide fully optimum stability and lateral grip, particularly under camber. Such tires also suffer from excessive tread wear under acceleration at high camber angles particularly when the tire is oversteering. It therefore an object of the present invention is to improve the properties of such tires.